Optical discs are discs that hold video, sound or computer data, for example compact discs (CDs), CD-ROMs, DVDs and Blu-Ray Discs®. (The term “BLU-RAY DISC” is a registered trade-mark of the Blu-Ray Disc Association, having an address at 10 Universal City Plaza, T-100, Universal City, Calif. 91608.). Optical discs usually have an identification code, for example as a bar code or in alphanumeric format, to identify what is on the disc. For optical discs such as CDs, CD-ROMs, DVDs and Blu-Ray Discs, the identification codes are usually carried on an annular portion of the disc near the central aperture therein, within an annular band having an inner diameter of approximately 33 mm and an outer diameter of approximately 47 mm. Typically, the identification code is molded into the disc at the time that the disc is manufactured.
Optical readers are used to read the identification code so that the contents of an optical disc can be readily identified. Such optical readers are used for example by sellers of optical discs who ship those optical discs to customers, an optical reader being used to ensure that a customer is being shipped the intended optical disc. Generally, an optical reader will capture an image or video stream of the identification code, and then transmit it to a computer running software capable of extracting the relevant information from the image or video stream.
Prior art optical readers have used a ring light source, i.e. an annular array of lights, with a sensor such as a camera positioned to view the optical disc through the aperture of the ring light source, so that light would be reflected back to the camera from the region of the optical disc containing the identification code.